Hi,
It would help if you gave more info on your plans, such as how many days total you are going to be in Japan. Also whether or not you are arriving and leaving Japan through KIX or some other airport.
You also appear to be putting the cart before the horse here - you need to decide your itinerary first, then decide the best way to get around. You've already mentioned (I presume) the JR Kansai Hokuriku Area Pass, which is a 7 day regional pass. So therefore you plan to travel around for more than 7 days, given your comments, is that correct?
If you need to squeeze out a few more days for your travel, you could use a JR Kansai Area Pass for the Kansai area, then a JR Hokuriku Area Pass for the Hokuriku area, and then return by bus or go to Nagoya and use a Kintetsu Rail Pass back to Kansai. But this is all stabbing in the dark here.
I suggest you look at all the regional passes and see what combination, if any, suits you best. To check to see if they'd pay off vs. regular train tickets, you can see regular fares, routes and schedules on Hyperdia.
If you are willing to forego going to Shirakawago, there is also Miyama which is in Kyoto.
Kyoto is worth several days, but don't skip Nara either. In Nara, the Todaiji Great Buddha is an extraordinary place, as well as many other historic temples, shrines and gardens in the area. After the temples of Kyoto close down around 5PM, you can zip over to Osaka for the evening. At night the city comes alive and has some great places to see, such as Dotonbori, plus the night views from the Umeda Sky Bldg, and Abeno Harukas Bldg are wonderful. On another evening, you could also go and see Kobe.
Good luck.
